The invention relates to an on-board computer for a motor vehicle according to the preamble of the main claim.
On-board computers for motor vehicles are frequently equipped with a microprocessor which acquires input signals from analog or digital generators and displays them on a display system. Frequently these include display texts or display values which must correspond to the language or the customary value dimensions of a country into which the motor vehicle is to be shipped. In this connection, it has become known, for example from the German Patent Document DE 32 33 833A1, to store several programs for processing the input signals in a program memory of the microprocessor. These arbitrarily selectable programs may be selected by way of an additional tip switch. An indicator which characterizes the selected program will then be displayed in the display system of the on-board computer.
Likewise, in VDI-Berichte 612 (VDI Reports 612) "Elektronik im Kraftfahrzeug" ("Electronics in the Motor Vehicle"), Conference/VDI Gesellschaft Fahrzeugtechnik (Society for Automotive Engineering) Dusseldorf: VDI-Verlag 1986, Baden-Baden, Oct. 9/10, 1986, on Pages 329 to 345, an information system for vehicles is described in which, where it is known during the production of the motor vehicle that the texts are to be displayed in the language of a specific country, a corresponding code is loaded into a nonvolatile storage area of the information system.
Thus, both systems result in a certain standardization of the information system for different destination countries of the motor vehicles. While in the former case, an additional switch is required for the change-over of the set of programs or data, the known information system does not require this type of a switch. However, the country-specific display is permanently established during the production and cannot be reprogrammed or can be reprogrammed only at very high expenditures at a later point in time, for example, when the vehicle is to be sold into a foreign country.
In the DE-35 40 599 A1 and in the VDI-Berichte (VDI-Reports) "Elektronik im Kraftfahrzeug" ("Electronics in the Motor Vehicle") Baden-Baden Conference, Sept. 8/9, 1988, Pages 315 to 338, an on-board computer is also described which has a display system that is arranged in an instrument cluster of a dashboard of a motor vehicle. The on-board computer is adapted to perform the function of a diagnostic system for several control units which are installed in the motor vehicle. For this purpose, the on-board computer is changed over to a diagnostic mode by means of a diagnostic connector. A function switch is used for the selection of the display functions in the on-board computer mode and for the accumulation control of the diagnostic analysis in the diagnostic mode.
It is an object of the present invention to provide an on-board computer for a motor vehicle by which a set of programs or data or display values or display data can be freely selected by simple means, without the requirement of using additional input elements at the on-board computer or having to reprogram the on-board computer.
This object is achieved by using the function switch of the on-board computer in place of a tip switch for the free selection of a specific (particularly country-specific) set of programs or data or display values or display data and by the fact that the selection takes place in a diagnostic mode of the on-board computer. The principal advantages of the invention are that a specific set of programs or data or display values or display data can be freely selected from a plurality of sets without additional input elements at the on-board computer or extensive reprogramming operations at the on-board computer.